ABSTRACT
86A new highly active and stereo regular Cobalt alkyl xhanthogenate + trialkylaluminum catalytic dithiosystems for obtaining highly crystalline syndiotactic 1,2-polybutadiene have been developed. Activity and stereo regularity of these catalysts in comparison with known cobalt-containing catalytic dithiosystems of butadiene polymerization, dependence of process outcomes on the nature of ligands of cobalt-compounds, catalyst components concentration and ratio, as well as the influence of temperature on catalyst activity and selectivity were studied. These catalysts in toluene solution showed very high activity and stereo regularity in butadiene polymerization: butadiene conversion—50.0-99.0%, 1,2-content—94.0-99.0%, intrinsic viscosity—1.3-3.5 dL/g; crystallinity—63.0-98.0%, syndiotacticity—93.0-98.5%, melting point—175-212°C. The optimal parameters of synthesis of high molecular mass and highly crystalline syndiotactic 1,2 -polybutadiene: [Co] = (1.0-2.0)·10−4 mol/L; [M] = 3.0 mol/L; Al:Co = (50-100):1; T = 40-80°C was established.
Highly crystalline syndiotactic 1,2-polybutadiene (1,2-SPBD) has higher izod strength, lower initial modulus, and lower thermal distortion temperature than polypropylene in spite of the higher melting point. Owing to the reactive vinyl group, the reaction of 1,2-SPBD (cross linking, cyclization and introduction of new functional groups) can easily proceed by the action of peroxide, radiation, or cationic reagents. The swelling resistances are good in contact with aliphatic, aromatic, or halogenated solvents. The 1,2-SPBD is chemically stable against water, base, and acids such as acetic acid and hydrogen chloride.
